cancer treatment varies. For most women it develops within 1 year of treatment, but for others it can occur up to 4 years or more following treatment (Mortimer et al., 1996). The risk appears to vary by extent of treatment with surgery and radiotherapy; however, the relative contributions of these interventions to the development of lymphedema is not clearly understood. Prospective studies of lymphedema are needed that use consistent definitions and measures.12

Lymphedema frequently occurs among women who have lymph nodes removed to determine the extent of cancer spread. Until the late 1990s, most women with early breast cancer had a procedure called axillary dissection, where some or all of the lymph nodes in the armpit area near the affected breast were removed. In 1994, a procedure called sentinel lymph node biopsy was tested on women with breast cancer in an effort to reduce the morbidity associated with axillary dissection while preserving the diagnostic utility of examining lymph nodes for evidence of cancer (Posther et al., 2004).13 Evidence of the effectiveness of sentinel lymph node biopsy will be available toward the end of the decade at the conclusion of clinical trials now underway (National Surgical Adjuvant Breast and Bowel Project, 2004; White and Wilke, 2004; Krag et al., 2004; Posther et al., 2004).14 In the meantime, sentinel lymph node biopsy is widely used in the United States, especially at major cancer centers. Estimates are that sentinel lymph node biopsy, if proven effective, could save 70 percent of women with negative findings at physical examination and negative pathology results following sentinel lymph node biopsy from the morbidity of immediate, complete axillary dissection (Schwartz, 2004). Some descriptive studies suggest that sentinel lymph node biopsy significantly reduces the occurrence of arm lymphedema among women with breast cancer (Blanchard et al., 2003b).

12

Variability in study design and lymphedema assessment in available studies make it difficult to draw firm conclusions regarding lymphedema’s etiology, natural history, and risk factors. Many of the studies are retrospective and may underestimate incidence because of a lack of documentation in the medical record or a failure on the part of clinicians to check for lymphedema. Other studies rely on patient self-reports, which may reflect different impressions of lymphedema.

13

Sentinel node biopsy relies on techniques to identify the “sentinel” node, the first node likely to be invaded by cancer. This technique involves injecting substances into the breast that enter the lymph system and concentrate in what is thought to be the sentinel node. This node can be identified and removed to test for cancer. If no cancer is detected, the remainder of the lymph nodes are spared.

14

Two cooperative groups sponsored by the National Cancer Institute, the National Surgical Adjuvant Breast and Bowel Project and the American College of Surgeons Oncology Group, initiated three multicenter clinical trials in 1999. Accrual of patients for two of the trials was completed in 2003 and 2004. With endpoints including 5-year survival, final results of the trials will not be available until the end of this decade (Posther et al., 2004).

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